Tsai Dung-Sheng, Chiang Ping-Yu, Tsai Meng-Lin, Tu Wei-Chen, Chen Chi, Chen Shih-Lun, Chiu Ching-Hsueh, Li Chen-Yu, Uen Wu-Yih
Department of Electronic Engineering, Chung Yuan Christian University, Taoyuan City 32023, Taiwan.
Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan.
Micromachines (Basel). 2020 Aug 27;11(9):812. doi: 10.3390/mi11090812.
This work demonstrates a self-powered and broadband photodetector using a heterojunction formed by camphor-based chemical vaper deposition (CVD) bilayer graphene on p-Si substrates. Here, graphene/p-Si heterostructures and graphene layers serve as ultra-shallow junctions for UV absorption and zero bandgap junction materials (<Si bandgap (1.1 eV)) for long-wave near-infrared (LWNIR) absorption, respectively. According to the Raman spectra and large-area (16 × 16 μm) Raman mapping, a low-defect, >95% coverage bilayer and high-uniformity graphene were successfully obtained by camphor-based CVD processes. Furthermore, the carrier mobility of the camphor-based CVD bilayer graphene at room temperature is 1.8 × 10 cm/V·s. Due to the incorporation of camphor-based CVD graphene, the graphene/p-Si Schottky junctions show a good rectification property (rectification ratio of ~110 at ± 2 V) and good performance as a self-powered (under zero bias) photodetector from UV to LWNIR. The photocurrent to dark current ratio (PDCR) value is up to 230 at 0 V under white light illumination, and the detectivity (*) is 8 × 10 cmHz/W at 560 nm. Furthermore, the photodetector (PD) response/decay time (i.e., rise/fall time) is ~118/120 μs. These results support the camphor-based CVD bilayer graphene/Si Schottky PDs for use in self-powered and ultra-broadband light detection in the future.
这项工作展示了一种自供电宽带光电探测器,它利用基于樟脑的化学气相沉积(CVD)在p-Si衬底上形成的双层石墨烯异质结。在此,石墨烯/p-Si异质结构和石墨烯层分别作为用于紫外吸收的超浅结和用于长波近红外(LWNIR)吸收的零带隙结材料(<Si带隙(1.1 eV))。根据拉曼光谱和大面积(16×16μm)拉曼映射,通过基于樟脑的CVD工艺成功获得了低缺陷、覆盖率>95%的双层且高均匀性的石墨烯。此外,基于樟脑的CVD双层石墨烯在室温下的载流子迁移率为1.8×10 cm/V·s。由于引入了基于樟脑的CVD石墨烯,石墨烯/p-Si肖特基结表现出良好的整流特性(±2 V时的整流比约为110),并且作为自供电(零偏压下)的光电探测器,从紫外到LWNIR都具有良好性能。在白光照射下,0 V时的光电流与暗电流之比(PDCR)值高达230,在560 nm处的探测率(*)为8×10 cmHz/W。此外,该光电探测器(PD)的响应/衰减时间(即上升/下降时间)约为118/120μs。这些结果支持基于樟脑的CVD双层石墨烯/Si肖特基光电探测器在未来用于自供电和超宽带光探测。